We ran into similar problems and it was ... not funny! The problem for us was that the installation script of IsoDraw and the licensing application didnâ€™t not look at the same network board when gathering the mac address (CPU-id)! This resulting in exactly what you are experiencing. So this is what we had to do: Uninstall the non-working ISODraw. Open a command prompt window (the DOS style window), type ipconfig /all There will be a list generated with all your network board and their details. Most likely you will have more than one networkboard (this was the problem for us)... In the "Description" locate what you feel is the used networkboard, write down the mac address for this board and exit the command prompt window. But, since we initially installed IsoDraw using a license file generated from the wrong mac id, IsoDraw still refused to start. And now we really get into bits and pieces, we also needed to clean the registry! Fiddling with the registry is not something you should do unless you have installed IsoDraw with a faulty license, do not change anything else than described below! Click on "start" and "run", type â€œregeditâ€�, in the registry editor click on â€œeditâ€� and â€œfindâ€�, type PTC_D_LICENSE_FILE Deep down in the registry you will find not one but at least two â€œkeysâ€� (I now have four of them), delete all keys that have a â€œdataâ€� value stating â€œc:\programfiles(x86)\PTC\Arbortext IsoDraw 7.1\lm_xxxxxxx.txtâ€� or similar as well (needed for a clean installation)! Please note that if youâ€™re running other PTC apps you might have other keys that is similar in look, DO NOT delete these! Exit reg edit and reboot your computer. Regenerate your license file using the mac id you noted down earlier, install. Hopefully your IsoDraw will start!